Messages in this thread Patch in this message |  | | | Date | Wed, 30 Apr 2003 22:59:56 -0400 | | From | Ben Collins <> | | Subject | Re: [PATCH] Fix NULL handler for compat_ioctl |
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On Wed, Apr 30, 2003 at 07:41:24PM -0700, Andrew Morton wrote: > Ben Collins <bcollins@debian.org> wrote: > > > > - t->handler = handler; > > + if (!handler) > > + t->handler = (void *)sys_ioctl; > > + else > > + t->handler = handler; > > Is that safe? > > - sys_ioctl takes three args, but this vector is going to be called with > four. That's making assumptions about arg passing conventions which may > not be true. > > - sys_ioctl() is asmlinkage, but the caller of this vector doesn't know > that. Arguments may get put in the wrong place.
Out of all the register_ioctl32_conversion functions that were consolidated with this patch, only s390 and x86_64 did not already use this same convention. linux/ioctl32.h already documents (and has always been that way) this feature.
Maybe you feel better about this patch instead? Moved the logic directly to compat_sys_ioctl. Also note that sys_ioctl is prototyped in include/linux/ioctl32.h.
Index: fs/compat.c =================================================================== RCS file: /home/scm/linux-2.5/fs/compat.c,v retrieving revision 1.8 diff -u -u -r1.8 compat.c --- linux/fs/compat.c 30 Apr 2003 16:17:21 -0000 1.8 +++ linux/fs/compat.c 1 May 2003 03:18:46 -0000 @@ -300,7 +300,6 @@ { struct file * filp; int error = -EBADF; - int (*handler)(unsigned int, unsigned int, unsigned long, struct file * filp); struct ioctl_trans *t; filp = fget(fd); @@ -317,8 +316,10 @@ while (t && t->cmd != cmd) t = (struct ioctl_trans *)t->next; if (t) { - handler = t->handler; - error = handler(fd, cmd, arg, filp); + if (t->handler) + error = t->handler(fd, cmd, arg, filp); + else + error = sys_ioctl(fd, cmd, arg); } else if (cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) { error = siocdevprivate_ioctl(fd, cmd, arg); } else { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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